Track usage of the clipping app

[phargogh]

Although we have some observability on the clipping app through GCP Cloud Run, we don't really have a concrete, long-lived tracking record of how often the clipping app is invoked. This would be good to track somehow.

It would be helpful to link this into our Google Analytics for the rest of the data hub, including:

• Which dataset is being clipped
• the clipping parameters
• The other activity this particular user/session had on the data hub

[phargogh]

Although GA might still be useful if we can link into it, I think a key aspect of this might actually be in the modification of the user agent so that we can see clipping app usage reflected in our bucket logs. Looks like GDAL allows the user agent to be configured: https://gdal.org/en/stable/user/configoptions.html#config-GDAL_HTTP_USERAGENT